"Together, we're going to make duets great again."

Jimmy Fallon's Donald Trump and Barbra Streisand took the stage together on Thursday for an inspired — and contentious — duet performance.

"Together, we're going to make duets great again," said Fallon as Trump as they introduced the song. "That's if you can sing," retorted Streisand.

"I sing all of the best words," bragged Fallon's Trump.

The song they picked was "Anything You Can Do," appropriate for their faux tension. Fallon's Trump was all about changing the words to fit his immigration plan. "I can build any wall taller than you," he sang.

Streisand was ready with her comebacks. At one point, she spoke about how she's going to vote for Hillary Clinton, who will "win huuuuge." Trump wasn't too pleased with her for that one, and the duet got derailed when he suffered a hair mishap.